Precision Machinery Research and Development Center (PMC) Builds Range of Industrial Robots with IntervalZero’s RTOS Platform and KingStar IO

Background and Challenges
Precision Machinery Research and Development Center (PMC) is a Taiwan-based company created in 1993 by the government and the Association of Machinery Industry (TAMI). PMC has teams of engineers from all fields related to machinery, including mechanical engineering, electrical engineering, control engineering, and information technologies. PMC conducts research and development in association with universities and not only transfers newly developed technologies to Taiwanese machinery companies, but also helps train their engineers. This approach allows the Taiwanese machinery industry to be a leader in performance and quality.

In recent years the economics of the machine industry have pushed companies toward the use of industrial robots. Although many machine building companies have built and demonstrated robots throughout Asia, they have significant difficulties achieving the required precision and performances.

With expertise in both mechanical engineering and control engineering PMC set out to build a wide range of quality industrial robots to match the different use cases in the industry. PMC looked for the right tools and technologies to build not only a single robot controller, but also a total solution that can control multiple robots as well as the other components to be used in combination with those robots such as machine vision or conveyor control.

Their search for the technologies that would offer such flexibility led them to PC-based control and network-based real-time protocols. The main advantage of these technologies is that you can use the same program for multiple types of robots or other controllers. The only adjustments required are matching the processor and memory to each application. Network protocols are also very important for this kind of flexibility because they allow you to change the motion and sensor hardware without changing or adding boards to the control computer.

Numerous Taiwan companies use PMC’s machine technology and each has its own preference concerning the hardware, such as motor drives or input cards. For this reason PMC chose to use the EtherCAT network protocol. EtherCAT, originally developed by Beckhoff, is now an open standard widely used in the industry and most hardware vendors have an EtherCAT version of their hardware. As PMC develops the technology and control based on a standard, the various companies in the industry can use it while still maintaining flexibility in their hardware choices.

But hardware flexibility comes at a cost. EtherCAT requires a complex configuration, which differs for each hardware. Testing and learning how to use each hardware is time consuming. Additionally, battling with protocol issues is not the purpose of PMC, which sought a way to maintain the hardware flexibility, while overcoming the testing, learning and protocol challenges.

A Partnership in a Mature Platform
After testing multiple EtherCAT solutions, PMC chose the IntervalZero RTX Real-time Operating System Platform (RTOS) with the KingStar IO EtherCAT as the best way forward.

As the demand increased throughout Asia for a simpler interface to use EtherCAT, IntervalZero responded by building a team in Taiwan dedicated to that task. IntervalZero formed a new company, KingStar, and developed the KingStar IO product; a plug-and-play software interface for EtherCAT which detects the machine hardware eliminates the need for complicated, time-consuming hardware testing and configuration.

While developing their technology and working with their partner companies PMC also had new demands in terms of EtherCAT options and hardware support. The King-Star IO team is working together with PMC to add the new functionalities to the platform and test any new hardware that was required.

As part of the partnership the KingStar IO team visited multiple companies, working with them to make sure the hardware they used would work properly. While performing tests and learning more about market needs the KingStar IO team has developed relationships with many of the EtherCAT drives and input/output module vendors and shared the technical requirements of the Taiwanese machine builders to help ensure that PMC’s technology can be used with a wide range of hardware without requiring many modifications in the control algorithms.

IntervalZero and PMC have also begun working on ways to enhance PMC’s solution with other components such as real-time vision control.

A Splendid Result
PMC showed the results of their work during the Taiwan Automation Intelligence and Robot show (TAIROS) in 2014. They deployed multiple types of robots and solutions that impressed all incoming visitors.

An ability to integrate any hardware
One of the demonstrations showed the ability to integrate hardware from different vendors on a 6-axis robot arm controller using various EtherCAT drives. Observers could see the motors follow the moves of the simulated arm even though they each had different specifications.

The challenge of 6-axis robot arms
Like many others PMC demonstrated the popular 6-axis robot arm. A challenge of this architecture is with bigger sizes and heavier loads, the load-variation can be significant and difficult to handle. PMC successfully showed their expertise with a bigger model, similar to those used in the automotive industry.

A total solution
PMC also showed that its architecture allowed for a total solution with Delta type robots, SCARA type robots and machine vision synchronized with one conveyor belt. The demonstration used three controller computers in combination, but PMC also has the ability to put all the robots in one controller.

Dual arm robot
The most impressive demonstration was two 7-axis robot arms linked together and controlled by a single computer. The 7-axes allow the robot arm to have the same degrees of liberty as a human arm and with this architecture they can co-work on a single piece just like a human would with two arms. Thanks to EtherCAT, RTX and the available power of recent processors the whole control can be done in a single, fanless computer which is quite small in size.